The Alabama tornadoes were spawned by a collision between warm, humid air from the Gulf of Mexico and a large cold front that dipped into the South from the Great Plains, said Mark Rose, a National Weather Service meteorologist in Birmingham.

Tornadoes hit Alabama

A series of rare winter tornadoes hit Alabama early Monday morning, and combined with powerful thunderstorms and straight-line winds, toppled trees and power lines and ripped apart homes and businesses. Two people were reported killed and at least 100 injured, and a state of emergency was declared.